研究了WC-6Co-1.5Al硬质合金球磨粉末的电流烧结工艺对合金性能的影响.结果表明：在脉冲电流基值、峰值、频率和占空比分别为360 A,3 000 A,50 Hz和50%时,在恒流电流为1 500 A,总烧结时间为6 min,烧结压力为30 MPa的工艺参数下,采用1 min脉冲+5 min恒流电流烧结工艺,WC平均晶粒尺寸约为500 nm,合金的密度、硬度和抗弯强度分别达到最大值14.22 g/cm3,94 HRA和1 660 MPa;与1 min脉冲+5 min恒流烧结工艺相比,采用单一的恒流电流烧结,通过增大恒流强度可进一步提高最大烧结密度,但同时合金的硬度和横向断裂强度均相对降低.

The fabrication of WC-6Co-1.5Al (wt%) hardmetals by electric current sintering from milled powders was studied.When the peak,base,repetition frequency and duty ratio of pulse electric current are prechoosed as 3 000 A,360 A,50 Hz and 50%,constant current,sintering pressure and total sintering time are prechoosed at 1 500 A,30 MPa and 6 min,the alloy has optimal properties by sintering of 1min pulse electrical current and subsequent 5 min constant electrical current.The density,hardness and transverse rupture strength of the as sintered alloy are 14.22 g/cm3,94 HRA and 1 660 MPa,respectively.The corresponding average WC grain size is about 500 nm.In the case of single constant current being supplied to sinter milled powders,the sintered density could be increased by intensifying the current,even being more than 14.22 g/cm3.However,too intensive constant current reduces the sintered density reversely.It is proved that the hardness and transverse rupture strength by single constant current sintering are lower than that by the sintering of 1min pulse- and 5min constant current.